In the above, creationTime, tokenKey and extendedInformation
are equal to that stored in Token. The Sha512Hex includes the same payload,
plus a serverSecret.

The serverSecret varies every millisecond. It relies on two static server-side secrets. The first
is a password, and the second is a server integer. Both of these must remain the same for any issued keys
to subsequently be recognised. The applicable serverSecret in any millisecond is computed by
password + ":" + (creationTime % serverInteger). This approach
further obfuscates the actual server secret and renders attempts to compute the server secret more
limited in usefulness (as any false tokens would be forced to have a creationTime equal
to the computed hash). Recall that framework features depending on token services should reject tokens
that are relatively old in any event.

A further consideration of this class is the requirement for cryptographically strong pseudo-random numbers.
To this end, the use of SecureRandomFactoryBean is recommended to inject the property.